The primary objectives of biostatistics as a core resource in the GI Cancer SPORE are design of studies, ongoing monitoring as needed, producing quality control databases for ongoing studies, and state-of- the-art statistical analyses. The guiding philosophy will be to keep quantitative aspects of the research closely tied to the specific aims, and to have the collaboration of the investigator and biostatistician such that the biologic knowledge of the researcher plays an integral part in shaping the statistical analyses. The resource will be made available to the SPORE projects via a statistician who has knowledge of these key core components. To achieve these objectives, the core biostatistician will be constantly available to SPORE investigators. Discussion of study aims, objectives, appropriate design parameters (i.e. study structure and sample size), the appropriate response to interim analyses, analytical plans and guidance for publication related issues will be provided whenever needed. All analyses will use the most current methods and will be conducted or supervised by the statistician. Because many of these analyses are exploratory and are meant to assess new methods, there will be emphasis on estimation of important clinical and laboratory parameters with confidence intervals and likelihood/Bayesian methodology rather than statistical hypothesis testing. The core statistician has experience in a number of areas of particular value to core investigators; inference in situations where there is relatively little empirical data, analysis of clinical research with small numbers of subjects, gene expression in GI tumors, and evaluation of cancer screening tests.